I think it's a fun idea for sure and forgetting competitive meta for a moment it should be fun to play.
I wouldn't discourage you from using Tervigons as I play them myself and have fun but they can be detrimental to your army once they die. Synaptic backlash is a big pain.
I know that taking the Swarmlord seems fun but he is so slow no one is ever going to let you get into
CC with him. Personally if I were going to do something similar to this list I would do it like this
-Remove Swarmlord and Tyrant Guard
-Remove two tyrannocytes
+2 X Flying Hive Tyrants with 2 Brainleech Devourers & Hive Commander (gives a troop choice outflank)
+Aegis Defense Line w/ Comms Relay (for reserve re-roll)
keep everything else the same (even though I would split the carnifex into three separate broods.)
This way you aren't investing so much into a beatstick boss monster who won't ever see combat and you can essentially split him into two synapse giving
HQ's that also allow for your Tervigons to outflank. I LOVE doing this. (although normally I only do it with one Tervigon and then outflank a unit of devil gaunts

)
But... no one plays non-flyrant nids to be competitive these days any way so if you're just doing it for fun keep your list as is. These are just a few thoughts.